
Here is the problem that people have with iOS 7 icons, MOST are very happy with the functionality of the system, that is NOT the main problem. It's this lazy sloppy icon design that makes a mess of the UI.
Let's see what consistency we have to create a "feel" for iOS 7 -
Dayglo colours? Nope, they feature on around half of the new icons while the others are flat and grey/black/white.
Flat colours? Nope, Game Centre bucks the trend with highlighted and shadowed "bubbles".
Consistent gradients (on those icons that have them), nope, half go from bright to dark, the rest the other direction.
Fully coloured rounded squares? Nope, some are but a few have oddly white backgrounds (full white could be considered as the "colour" in the case of Calendar but not the others).
All graphical content either fills the rounded square or fits into an internal square (sorry, getting a little "designery" here) - nope, half take up the entire square while half fit into a smaller, internal square.
I could go on but this is getting my point across, there is just no consistent visual design to iOS 7. That said, I and many others still like the overall system - we just expect more polish from Apple. More competence in design than this mish-mash, that is why people are disappointed* Those that blindly praise everything Apple do will not help the company progress but as they are here actually start to regress...
*We know it's only a Beta but that's all we have to go on at present and Apple rarely change the fundamentals from Beta.